When we built the Lake of the Ozarks

It is the year 1931, and the Union Electric Co. has just completed the construction of the massive Bagnell Dam on the Osage River.

“It stands as a monument to the courage and vision of men, an awe-inspiring engineering triumph, impressive and majestic through its 2543 feet of length,” the June 1931 issue of our magazine marveled.

Union Electric, now known as Ameren Missouri, began building the dam in August 1929 and finished in only two years. It is a concrete gravity dam, which means its weight is enough to overcome the lateral force of the water pressing against it. The cost was about $30 million — more than $430 million in today’s money.

“Ordinarily the Osage is a sleepy and friendly stream but capable of raging destructive fury when in flood,” the author wrote. The ambitious undertaking to harness that energy was “the first large step in Missouri water power development.”

Beforehand, the river was studied for more than two years to determine its maximum and minimum flows as well as the geologic formation. Researchers found “a free basin with little or no seepage,” a nearly perfect location.

An average of 3,000 people at a time were employed to work on the dam. To accommodate them, a “model town of five to six thousand population was established at the dam to provide facilities,” the article stated. Railways, houses, dorms, dining halls, stores, a school, a jail and a hospital were among the facilities built to support the massive construction efforts.

The article noted the fun fact that “a world’s record for concrete pouring was made at Osage when 5,082 cubic yards of concrete was poured in a single 24-hour day.” It’s no wonder the dam was so swiftly completed.

Another interesting tidbit from the original story is its mention of the use of aerial photography. What is considered a normal, inexpensive process now was a remarkable and innovative technology in the ’30s. To locate the most direct line through the Ozarks’ mountains and forests, “the airplane rendered a new and helpful service,” the author wrote. “Photographic surveys for the transmission lines were made by aerial cameras from five thousand feet in the air.”

The dam was named after Bagnell, Missouri, a town that preceded it. The town itself was named after William Bagnell, a railroad man who platted it back in 1883.

“In the average year the initial Osage plant will deliver over (400 million) kilowatt hours of electric energy to St. Louis, Rivermines, and points on the Union Electric inter-connected system,” which was the equivalent of 270,000 tons of coal, according to the article. The impressive final structure had a capacity “ten times that of the total water power in the state in 1929.”

Since then, upgrades to the dam have boosted output to 500 million kilowatt-hours per year, or enough to power 42,000 average households. And with the launch of an 18-month, $52 million dam maintenance project this spring, Ameren plans to ensure that the dam remains in top condition for decades to come. The project is the largest and most visible work done on the site in over 30 years and includes new post-tension anchors to further secure the dam to the bedrock, added concrete between the highway piers to add weight and some fresh concrete overlay to replace weathered concrete.

Though the dam was constructed primarily for energy production, it also greatly aided in “flood control on the lower Osage, where high water has in the past been a serious menace.” The creation of the 92-mile Lake of the Ozarks was another rich opportunity. The lake boasts 1,100 miles of shoreline, which is longer than the coastline of the state of California, and at the time it was the largest manmade lake in the U.S.

The lake “is a distinct addition to the playgrounds of Missouri and of the United States. It will afford the pleasures of scenic grandeur and aquatic sports for which Missourians now travel hundreds of miles to enjoy,” the 1931 article predicted.

And it was right — today the lake area is bustling with businesses and tourists. Every year between Memorial Day and Labor Day, it attracts approximately 3.5 million visitors.

“Power attracts industry,” the article concluded. “A lazy river has been put to work for the benefit of mankind.”